Spectroscopy module

ABSTRACT

In a spectroscopy module  1 , a light passing hole  50  through which a light L 1  advancing to a spectroscopic portion  4  passes is formed in a light detecting element  5 . Therefore, it is possible to prevent the relative positional relationship between the light passing hole  50  and a light detecting portion  5   a  of the light detecting element  5  from deviating. Moreover, the light detecting element  5  is bonded to a front plane  2   a  of a substrate  2  with an optical resin adhesive  63 . Thus, it is possible to reduce a stress generated onto the light detecting element  5  due to a thermal expansion difference between the light detecting element  5  and the substrate  2 . Additionally, the light transmissive plate  16  covers a part of a light incident opening  50   a . Thus, a light incident side surface  63   a  of the optical resin adhesive  63  becomes a substantially flat plane in the light passing hole  50 . Therefore, it is possible to make the light L 1  appropriately incident into the substrate  2.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a spectroscopy module for dispersinglight to detect the light.

2. Related Background of the Invention

There is known such a conventional spectroscopy module described in, forexample, Japanese Published Unexamined Patent Application No. H04-294223(Patent Document 1) and Japanese Published Unexamined Patent ApplicationNo. 2004-354176 (Patent Document 2). Patent Document 1 has described aspectroscopy module which is provided with a supporting body throughwhich light is allowed to transmit, an incident slit portion throughwhich light is made incident into the supporting body, a concavediffraction grating that disperses the light made incident into thesupporting body to reflect the light, and a diode that detects thelights dispersed and reflected by the concave diffraction grating.

SUMMARY OF THE INVENTION

However, in the spectroscopy module described in Patent Document 1, whenthe incident slit portion and the diode are attached to the supportingbody, the relative positional relationship between the incident slitportion and the diode may deviate, thereby degrading the reliability ofthe spectroscopy module.

The present invention has been achieved in consideration of theabove-described circumstances, and an object of the present invention isto provide a highly reliable spectroscopy module.

In order to achieve the above-described object, the spectroscopy moduleaccording to the present invention is provided with a body portionthrough which light is allowed to transmit, a spectroscopic portion thatdisperses a light made incident into the body portion from a side of apredetermined plane of the body portion, to reflect lights to the sideof the predetermined plane, and a light detecting element which isattached to the predetermined plane via an optical resin adhesive, anddetects the lights dispersed by the spectroscopic portion, and in thespectroscopy module, a light passing hole through which a lightadvancing to the spectroscopic portion passes is formed, and terminalelectrodes facing a side opposite to the body portion are provided inthe light detecting element, and a part of a light incident opening ofthe light passing hole is covered with a light transmissive plate.

In the spectroscopy module, the light passing hole through which a lightadvancing to the spectroscopic portion passes is formed in the lightdetecting element. Therefore, it is possible to prevent the relativepositional relationship between the light passing hole and the lightdetecting portion of the light detecting element from deviating.Moreover, the light detecting element is attached to the predeterminedplane of the body portion via the optical resin adhesive. Thus, it ispossible to reduce a stress generated onto the light detecting elementdue to a thermal expansion difference between the light detectingelement and the body portion. Additionally, the part of the lightincident opening of the light passing hole is covered with the lighttransmissive plate. Thus, for example, when the light detecting elementis attached to the predetermined plane of the body portion via theoptical resin adhesive, the part which is not covered with the lighttransmissive plate serves as an outgassing portion, to allow the opticalresin adhesive to penetrate into the light passing hole, and the lightincident side surface of the optical resin adhesive becomes asubstantially flat plane in the light passing hole. Therefore, it ispossible to make a light appropriately incident into the body portion.Therefore, according to the spectroscopy module, it is possible toimprove the reliability.

In the spectroscopy module according to the present invention, the lightpassing hole is preferably formed so that the light incident openingincludes the light emitting opening of the light passing hole whenviewed from a direction of its center line, and the light transmissiveplate preferably covers a part of the light incident opening so as toinclude the light emitting opening when viewed from the direction of thecenter line. In accordance with this configuration, the light emittedfrom the light emitting opening of the light passing hole passes throughthe light transmissive plate and the light incident side surface of theoptical resin adhesive made to be a substantially flat plane by thelight transmissive plate, which makes it possible to make the lightapproximately incident into the body portion.

In the spectroscopy module according to the present invention, a lightabsorbing layer having a first light passing portion through which thelight advancing to the spectroscopic portion passes, and a second lightpassing portion through which the lights advancing to the lightdetecting portion of the light detecting element pass, is preferablyformed on the predetermined plane. In this case, because stray light isprevented from being generated and stray light is absorbed by the lightabsorbing layer, it is possible to prevent stray light from being madeincident into the light detecting portion of the light detectingelement.

The spectroscopy module according to the present invention is preferablyfurther provided with a wiring board attached to the predeterminedplane, and in the spectroscopy module, an opening portion into which thelight detecting element is disposed is formed, and a wiring electricallyconnected to the terminal electrodes is provided in the wiring board.According to this configuration, it is possible to block a light that istrying to advance to the spectroscopic portion without passing throughthe light passing hole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a spectroscopy module as one embodimentaccording to the present invention.

FIG. 2 is a cross sectional view taken along the line II to II shown inFIG. 1.

FIG. 3 is a bottom view of the spectroscopy module of FIG. 1.

FIG. 4 is an enlarged plan view of a main part of the spectroscopymodule of FIG. 1.

FIG. 5 is an enlarged sectional view of a main part of the spectroscopymodule of FIG. 1.

FIG. 6 is a cross sectional view of a spectroscopy module as anotherembodiment according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a detailed description will be given to preferredembodiments of the present invention by referring to the drawings. It isnoted that in the individual drawings, the same reference letters ornumerals are given to the same and corresponding parts, with overlappingdescription omitted.

FIG. 1 is a plan view of a spectroscopy module as one embodimentaccording to the present invention, and FIG. 2 is a cross sectional viewtaken along the line II to II shown in FIG. 1. As shown in FIG. 1 andFIG. 2, a spectroscopy module 1 is provided with a substrate (bodyportion) 2 through which a light L1 made incident from a side of a frontplane (predetermined plane) 2 a is allowed to transmit, a lens portion(body portion) 3 through which the light L1 made incident into thesubstrate 2 is allowed to transmit, a spectroscopic portion 4 thatdisperses the light L1 made incident into the lens portion 3 to reflectthe light toward the front plane 2 a, and a light detecting element 5that detects lights L2 dispersed by the spectroscopic portion 4. Thespectroscopy module 1 is a micro-spectroscopy module that disperses thelight L1 into the lights L2 corresponding to a plurality of wavelengthsby the spectroscopic portion 4, and detects the lights L2 by the lightdetecting element 5, thereby measuring the wavelength distribution ofthe light L1, the intensity of a specific wavelength component, or thelike.

The substrate 2 is formed into a rectangular plate shape (with, forexample, an entire length of 15 to 20 mm, a full width of 11 to 12 mm,and a thickness of 1 to 3 mm), from light-transmitting glass such asBK7, Pyrex® and quartz, plastic, or the like. A resist layer 72 havingan opening portion 71 in a cross-sectionally rectangular shape intowhich the light detecting element 5 is fitted, is formed on the frontplane 2 a of the substrate 2 via a light absorbing layer 67. A wiringboard 51 in a rectangular plate shape, which has an opening portion 51 ain a cross-sectionally rectangular shape in which the light detectingelement 5 is disposed, is bonded to a front plane 72 a of the resistlayer 72 with a resin adhesive 53. The wiring board 51 is formed into arectangular plate shape (with, for example, an entire length of 15 to 20mm, a full width of 11 to 12 mm, and a thickness of 1 to 3 mm), which issubstantially the same as that of the substrate 2 so as to be smaller inentire length and full width than the substrate 2, from ceramic,plastic, polyimide, glass epoxy, an inorganic-organic hybrid material,silicon, or the like. The opening portion 51 a formed in the wiringboard 51 is formed so as to be larger than the opening portion 71 formedin the resist layer 72. A wiring 52 formed of a metal material isprovided to the wiring board 51. The wiring 52 has a plurality of padportions 52 a disposed around the opening portion 51 a, a plurality ofpad portions 52 b disposed at the both ends in the longitudinaldirection of the wiring board 51, and a plurality of connection portions52 c that connect the pad portions 52 a and the pad portions 52 b whichcorrespond to one another.

In addition, the light absorbing layer 67 formed on the front plane 2 aof the substrate 2 has a light passing hole (a first light passingportion) 67 a through which the light L1 advancing to the spectroscopicportion 4 passes via a light passing hole 50 (which will be describedlater) of the light detecting element 5, and a light passing hole (asecond light passing portion) 67 b through which the lights L2 advancingto a light detecting portion 5 a (which will be described later) of thelight detecting element 5 passes. As a material of the light absorbinglayer 67, colored resin (silicon, epoxy, acrylic, urethane, polyimide,or composite resin, or the like) including black resist or a filler(such as carbon or oxide), metal such as Cr or Co or metal oxidethereof, or a laminated film thereof, or porous-type ceramic, metal, ormetal oxide, can be cited.

FIG. 3 is a bottom view of the spectroscopy module of FIG. 1. As shownin FIGS. 2 and 3, the lens portion 3 is formed into a shape such that asemispherical lens is cut off along two planes substantiallyperpendicular to its bottom plane 3 a and substantially parallel to eachother to form its side planes 3 b (with, for example, a curvature radiusof 6 to 10 mm, an entire length of the bottom plane 3 a of 12 to 18 mm,a full width of the bottom plane 3 a (i.e., a distance between the sideplanes 3 b) of 6 to 10 mm, and a height of 5 to 8 mm), from a materialwhich is the same as that of the substrate 2, that is light-transmittingresin, a light-transmitting organic-inorganic hybrid material, orlight-transmitting low-melting point glass or plastic for replicamolding, or the like. The lens portion 3 is bonded to a rear plane 2 bof the substrate 2 with an optical resin adhesive 73 through which thelights L1 and L2 are allowed to transmit by using the outer edge portionof the substrate 2 such as the corners or the sides of the substrate 2as a reference portion. At this time, because the spectroscopic portion4 is positioned with respect to the lens portion 3 with high precision,the outer edge portion of the substrate 2 serves as a reference portionfor positioning the spectroscopic portion 4 at the substrate 2. Inaddition, the lens shape is not limited to a spherical lens, and may bean aspherical lens.

The spectroscopic portion 4 is a reflection type grating having adiffraction layer 6 formed on the outer surface of the lens portion 3, areflection layer 7 formed on the outer surface of the diffraction layer6, and a passivation layer 54 that covers the diffraction layer 6 andthe reflection layer 7. The diffraction layer 6 is formed so that aplurality of grating grooves 6 a are provided adjacent to each otheralong the longitudinal direction of the substrate 2, and the directionin which the grating grooves 6 a are extended is substantially matchedto a direction substantially perpendicular to the longitudinal directionof the substrate 2. For example, a cross-sectionally serrated blazedgrating, a cross-sectionally rectangular binary grating, across-sectionally sinusoidal holographic grating, or the like is appliedas the diffraction layer 6, and the diffraction layer 6 is formed bysubjecting optical resin for replica molding such as photo curing epoxyresin, acryl resin, or organic-inorganic hybrid resin to photo curing.The reflection layer 7 is a membrane form, and is formed by, forexample, evaporating Al, Au, or the like onto the outer surface of thediffraction layer 6. In addition, an optical NA of the spectroscopymodule 1 can be adjusted by adjusting an area on which the reflectionlayer 7 is formed. The passivation layer 54 is a membrane form, and isformed by, for example, evaporating MgF₂, SiO₂, or the like onto theouter surfaces of the diffraction layer 6 and the reflection layer 7.

As shown in FIGS. 1 and 2, the light detecting element 5 is formed intoa rectangular plate shape (with, for example, an entire length of 5 to10 mm, a full width of 1.5 to 3 mm, and a thickness of 0.1 to 0.8 mm).The light detecting portion 5 a is formed on the plane at the side ofthe spectroscopic portion 4 of the light detecting element 5. The lightdetecting portion 5 a is a CCD image sensor, a PD array, or a CMOS imagesensor or the like, and is formed so that a plurality of channels arearrayed in a direction substantially perpendicular to the direction inwhich the grating grooves 6 a of the spectroscopic portion 4 areextended (i.e., the direction in which the grating grooves 6 a areprovided adjacent to each other).

In the case in which the light detecting portion 5 a is a CCD imagesensor, light intensity information at a position at which the light ismade incident into pixels disposed two-dimensionally is subjected toline-binning, and to make the information into light intensityinformation at a one-dimensional position, the light intensityinformation at the one-dimensional position is read out in time-series.That is, a line of the pixels subjected to line-binning becomes onechannel. In the case in which the light detecting portion 5 a is a PDarray or a CMOS image sensor, because light intensity information at aposition at which the light is made incident into pixels disposedone-dimensionally is read out in time-series, one pixel becomes onechannel.

In addition, in the case in which the light detecting portion 5 a is aPD array or a CMOS image sensor, and pixels are arrayedtwo-dimensionally, a line of pixels arrayed in a direction of aone-dimensional array parallel to the direction in which the gratinggrooves 6 a of the spectroscopic portion 4 are extended becomes onechannel. Further, in the case in which the light detecting portion 5 ais a CCD image sensor, for example, a light detecting portion 5 a inwhich a space between channels in its array direction is 12.5 μm, anentire length of a channel (a length of a one-dimensional pixel rowsubjected to line-binning) is 1 mm, and the number of channels to bearrayed is 256 is used for the light detecting element 5.

Further, the light passing hole 50 through which the light L1 advancingto the spectroscopic portion 4 passes, that is provided adjacent to thelight detecting portion 5 a in the array direction of the channels, isformed in the light detecting element 5. The light passing hole 50 is aslit (with, for example, a length of 0.5 to 1 mm and a width of 10 to100 μm) which is extended in a direction substantially perpendicular tothe longitudinal direction of the substrate 2, and is formed by etchingor the like so as to be positioned with high precision with respect tothe light detecting portion 5 a.

FIG. 4 is an enlarged sectional view of a main part of the spectroscopymodule of FIG. 1, and FIG. 5 is an enlarged sectional view of a mainpart of the spectroscopy module of FIG. 1. As shown in FIGS. 4 and 5, aplurality of electrodes 58 are formed on the plane at the side of thespectroscopic portion 4 of the light detecting element 5, and aplurality of terminal electrodes 61 connected to the respectiveelectrodes 58 via feed-through electrodes 59 are formed on the planeopposite to the spectroscopic portion 4 of the light detecting element5. The respective terminal electrodes 61 facing the side opposite to thesubstrate 2 are connected to the corresponding pad portions 52 a of thewiring board 51 with wires 62. Thereby, the terminal electrodes 61 andthe wiring 52 are electrically connected, and electric signals generatedin the light detecting portion 5 a are led to the outside via theelectrodes 58, the feed-through electrodes 59, the terminal electrodes61, the pad portions 52 a, connection portions 52 c, and the padportions 52 b.

As shown in FIG. 5, the light detecting element 5 is fitted into theopening portion 71 of the resist layer 72, and is bonded to the frontplane 2 a of the substrate 2 with an optical resin adhesive 63 throughwhich the lights L1 and L2 are allowed to transmit. The opening portion71 is formed by photo-etching so as to have a predetermined positionalrelationship with respect to the outer edge portion of the substrate 2serving as a reference portion for positioning the spectroscopic portion4 to the substrate 2. In addition, the light detecting element 5 isprojected from the front plane 72 a of the resist layer 72 while beingfitted into the opening portion 71. Then, as shown in FIG. 4, side walls71 a into which the light detecting element 5 is fitted in the directionin which the grating grooves 6 a of the spectroscopic portion 4 areextended, and side walls 71 b into which the light detecting element 5is fitted in the direction substantially perpendicular to the directionin which the grating grooves 6 a of the spectroscopic portion 4 areextended are provided to the opening portion 71. Spaces between the sidewalls 71 b and the light detecting element 5 are made smaller thanspaces between the side walls 71 a and the light detecting element 5.

As shown in FIGS. 4 and 5, the light passing hole 50 has a lightincident side portion 50 ₁ that demarcates a light incident opening 50 athrough which the light L1 is made incident, and a light emission sideportion 50 ₂ that demarcates a light emitting opening 50 b from whichthe light L1 is emitted. The light emission side portion 50 ₂ is formedinto a rectangular parallelepiped shape which is extended in a directionsubstantially perpendicular to the longitudinal direction of thesubstrate 2, and the light incident side portion 50 ₁ is formed into asquare pyramid shape broadening toward the opposite side from the lightemission side portion 50 ₂. That is, the light passing hole 50 is formedso that the light incident opening 50 a includes the light emittingopening 50 b when viewed from the direction of its center line CL.

A part of the light incident opening 50 a of the light passing hole 50is covered with a light transmissive plate 16. The light transmissiveplate 16 is formed into a rectangular thin plate shape fromlight-transmitting glass or the like, and covers the part of the lightincident opening 50 a by leaving the edge along the longitudinaldirection of the light incident opening 50 a, so as to include the lightemitting opening 50 b when viewed from the direction of the center lineCL of the light passing hole 50. Thereby, a light incident side surface63 a of an optical resin adhesive 63 becomes a substantially flat planein the light passing hole 50. In addition, the light transmissive plate16 may cover a part of the light incident opening 50 a by leaving theedge along the direction substantially perpendicular to the longitudinaldirection of the light incident opening 50 a.

In the spectroscope module 1 configured as described above, the light L1is made incident into the substrate 2 from the side of the front plane 2a of the substrate 2 via the light transmissive plate 16, the lightpassing hole 50 of the light detecting element 5, and the light passinghole 67 a of the optical resin adhesive 63 and the light absorbing layer67, and advance inside the substrate 2, the optical resin adhesive 73,and the lens portion 3, to reach the spectroscopic portion 4. The lightL1 reaching the spectroscopic portion 4 is dispersed into lights L2corresponding to a plurality of wavelengths by the spectroscopic portion4. The dispersed lights L2, are not only dispersed by the spectroscopicportion 4, but also reflected toward the front plane 2 a of thesubstrate 2, and advance inside the lens portion 3, the optical resinadhesive 73, and the substrate 2 to reach the light detecting portion 5a of the light detecting element 5 via the light passing hole 67 b ofthe light absorbing layer 67 and the optical resin adhesive 63. Thelights L2 reaching the light detecting portion 5 a are detected by thelight detecting element 5.

A method for manufacturing the spectroscopy module 1 described abovewill be described.

First, the spectroscopic portion 4 is formed on the lens portion 3. Indetail, a light-transmitting master grating on which gratingscorresponding to the diffraction layer 6 are engraved is pushed onto theoptical resin for replica molding falling in drops near the tip of thelens portion 3. Then, the optical resin for replica molding is subjectedto light in this state to cure the optical resin for replica molding,and the optical resin for replica molding is preferably subjected tothermal curing for stabilization, to form the diffraction layer 6 havingthe plurality of grating grooves 6 a. Thereafter, the master grating isdemolded, and Al, Au, or the like is evaporated with a mask or isentirely evaporated onto the outer surface of the diffraction layer 6 toform the reflection layer 7. Moreover, MgF₂, SiO₂, or the like isevaporated with a mask or is entirely evaporated onto the outer surfacesof the diffraction layer 6 and the reflection layer 7 to form thepassivation layer 54.

Meanwhile, the substrate 2 is prepared, and the light absorbing layer 67having the light passing holes 67 a and 67 b is formed on the frontplane 2 a of the substrate 2. Moreover, the resist layer 72 having theopening portion 71 is formed on the front plane 2 a of the substrate 2via the light absorbing layer 67. In addition, the opening portion 71 isformed by photo-etching so as to have a predetermined positionalrelationship with respect to the outer edge portion of the substrate 2serving as a reference portion for positioning the spectroscopic portion4 to the substrate 2.

Next, the optical resin adhesive 63 is applied onto the front plane 2 aof the substrate 2 exposed in the opening portion 71 of the resist layer72, and the light detecting element 5 with the light transmissive plate16 is fitted into the opening portion 71, to be pressed onto the frontplane 2 a of the substrate 2. At this time, the part which is notcovered with the light transmissive plate 16 serves as an outgassingportion, to allow the optical resin adhesive 63 to penetrate into thelight passing hole 50, and the light incident side surface 63 a of theoptical resin adhesive 63 is made to be a substantially flat plane bythe light transmissive plate 16 in the light passing hole 50. Then, theoptical resin adhesive 63 is subjected to light to be cured, and thelight detecting element 5 is mounted onto the substrate 2. In addition,the light transmissive plate 16 may be attached after the lightdetecting element 5 is fitted into the opening portion 71 via theoptical resin adhesive 63, to be pressed onto the front plane 2 a of thesubstrate 2, and the inside of the light passing hole 50 is furtherfilled with the optical resin adhesive 63 from the light incidentopening 50 a. Thereafter, the lens portion 3 on which the spectroscopicportion 4 is formed is bonded to the rear plane 2 b of the substrate 2with the optical resin adhesive 73 by using the outer edge portion ofthe substrate 2 as a reference portion.

Next, the wiring board 51 is bonded to the front plane 72 a of theresist layer 72 with the resin adhesive 53. Then, the terminalelectrodes 61 of the light detecting element 5 and the pad portions 52 aof the wiring board 51 which correspond to one another are connectedwith the wires 62, to obtain the spectroscopy module 1.

As described above, in the spectroscopy module 1, the light passing hole50 through which the light L1 advancing to the spectroscopic portion 4passes, is formed in the light detecting element 5. Therefore, it ispossible to prevent the relative positional relationship between thelight passing hole 50 and the light detecting portion 5 a of the lightdetecting element 5 from deviating. Moreover, the light detectingelement 5 is bonded to the front plane 2 a of the substrate 2 with theoptical resin adhesive 63. Thus, it is possible to reduce a stressgenerated onto the light detecting element 5 due to a thermal expansiondifference between the light detecting element 5 and the substrate 2.Additionally, the light passing hole 50 is formed so that the lightincident opening 50 a includes the light emitting opening 50 b whenviewed from the direction of the center line CL, and the lighttransmissive plate 16 covers the part of the light incident opening 50 aso as to include the light emitting opening 50 b when viewed from thedirection of the center line CL. Thus, when the light detecting element5 is bonded to the front plane 2 a of the substrate 2 with the opticalresin adhesive 63, the part which is not covered with the lighttransmissive plate 16 serves as an outgassing portion, to allow theoptical resin adhesive 63 to penetrate into the light passing hole 50,and the light incident side surface 63 a of the optical resin adhesive63 becomes a substantially flat plane in the light passing hole 50.Therefore, the light L1 emitted from the light emitting opening 50 b ofthe light passing hole 50 passes through the light transmissive plate 16and the light incident side surface 63 a of the optical resin adhesive63 is made to be a substantially flat plane by the light transmissiveplate 16, and as a result, the light L1 is allowed to be approximatelymade incident into the substrate 2. Therefore, according to thespectroscopy module 1, it is possible to improve the reliability.

In addition, according to the optical resin adhesive 63 with which theinside of the light passing hole 50 is filled, it is possible tosuppress the light transmission characteristic for the short-wavelengthrange (that is, it is possible for the optical resin adhesive 63 toserve as a high-pass filter), which makes it possible to prevent straylight. Further, it is possible for light transmissive plate 16 to havean optical filter function.

Further, in the spectroscopy module 1, the light absorbing layer 67having the light passing hole 67 a through which the light L1 advancingto the spectroscopic portion 4 passes and the light passing hole 67 bthrough which the lights L2 advancing to the light detecting portion 5 aof the light detecting element 5 passes, is formed on the front plane 2a of the substrate 2. Because the light absorbing layer 67 preventsgeneration of stray light and absorbs stray light, it is possible toprevent stray light from being made incident into the light detectingportion 5 a.

Further, in the spectroscopy module 1, the wiring board 51 having thewiring 52 electrically connected to the terminal electrodes 61 of thelight detecting element 5 is bonded to the front plane 2 a of thesubstrate 2 in a state in which the light detecting element 5 isdisposed in the opening portion 51 a. According to the wiring board 51,it is possible to block a light that is trying to advance to thespectroscopic portion 4 without passing through the light passing hole50.

Further, in the spectroscopy module 1, because the opening portion 71 ofthe resist layer 72 has a predetermined positional relationship withrespect to the outer edge portion of the substrate 2 serving as areference portion for positioning the spectroscopic portion 4 to thesubstrate 2, the light detecting element 5 is positioned to thesubstrate 2 by merely fitting the light detecting element 5 into theopening portion 71. At this time, because the lens portion 3 on whichthe spectroscopic portion 4 is formed is positioned to the substrate 2in accordance with the outer edge portion of the substrate 2 serving asa reference portion, as a result, alignment of the spectroscopic portion4 and the light detecting element 5 is achieved. Additionally, thespaces between the side walls 71 b of the opening portion 71 and thelight detecting element 5 in a direction substantially perpendicular tothe direction in which the grating grooves 6 a of the spectroscopicportion 4 are extended are made smaller than the spaces between the sidewalls 71 a of the opening portion 71 and the light detecting element 5in the direction in which the grating grooves 6 a of the spectroscopicportion 4 are extended. Thereby, precisely performing alignment betweenthe lens portion 3 and the light detecting element 5 in a directionsubstantially perpendicular to the direction in which the gratinggrooves 6 a are extended, makes it possible to make the lights L2dispersed by the spectroscopy portion 4 accurately incident into thelight detecting element 5. Moreover, because the light detecting element5 is a rectangular plate shape, the spaces between the light detectingelement 5 and the side walls 71 a of the opening portion 71 are madelonger and the distances up to the spaces as well are made shorter inthe direction in which the grating grooves 6 a are extended, it ispossible to effectively allow excess resin or air out when the lightdetecting element 5 is bonded to the substrate 2 with the optical resinadhesive 63. In this way, according to the spectroscopy module 1,so-called passive alignment is achieved, which makes it possible tosimply assemble the module while maintaining the reliability.

Further, in the spectroscopy module 1, the light detecting element 5 isprojected from the front plane 72 a of the resist layer 72 while beingfitted into the opening portion 71. Thereby, it is possible, not only tomake a work of fitting the light detecting element 5 into the openingportion 71 provided in the front plane 72 a of the resist layer 72 easy,but also to reliably allow excess resin or air out by reliably pressingthe light detecting element 5 onto the front plane 2 a of the substrate2 exposed in the opening portion 71.

The present invention is not limited to the above-described embodiment.

For example, as shown in FIG. 6, the light absorbing layer 67 having thelight passing hole 67 a through which the light L1 advancing to thespectroscopic portion 4 passes and the light passing hole 67 b throughwhich the lights L2 advancing to the light detecting portion 5 a of thelight detecting element 5 passes, may be formed between the substrate 2and the lens portion 3. According to this configuration, it is possiblefor the light advancing while spreading to be limited so as to reach adesired area, and it is possible to effectively prevent stray light frombeing made incident into the light detecting element 5. Further, it ispossible to adjust an optical NA by differing the sizes of the lightpassing holes 67 a and 67 b in the light absorbing layer 67.

Further, as shown in FIG. 6, a so-called back-illuminated type elementmay be applied as the light detecting element 5. In this case, becausethe electrodes 58 are located outside along with the light detectingportion 5 a, the electrodes 58 may be used as terminal electrodes facingthe side opposite to the substrate 2, and the electrodes 58 may beconnected with the pad portions 52 a and the wires 62 of the wiringboard 51.

Further, it is not necessary to provide a portion into which the lightdetecting element 5 is fitted, to the substrate 2 by forming the resistlayer 72 or the like. Moreover, the substrate 2 and the lens portion 3may be integrally formed with a mold, and the lens portion 3 and thediffraction layer 6 may be integrally formed of light-transmittinglow-melting point glass for replica molding or the like. In addition,bonding of the light detecting element 5 onto the front plane 2 a of thesubstrate 2, formation of the light absorbing layer 67 onto the frontplane 2 a of the substrate 2, bonding of the wiring board 51 onto thefront plane 2 a of the substrate 2, and the like may be directly carriedout, and may be indirectly carried out via some layers in some cases.

In accordance with the present invention, it is possible to improve thereliability of the spectroscopy module.

1. A spectroscopy module comprising: a body portion through which lightis allowed to transmit; a spectroscopic portion that disperses a lightmade incident into the body portion from a side of a predetermined planeof the body portion, to reflect lights to the side of the predeterminedplane; and a light detecting element which is attached to thepredetermined plane via an optical resin adhesive, the light detectingelement detects the lights dispersed by the spectroscopic portion,wherein a light passing hole through which a light advancing to thespectroscopic portion passes is formed, and terminal electrodes facing aside opposite to the body portion are provided in the light detectingelement, and a part of a light incident opening of the light passinghole is covered with a light transmissive plate.
 2. The spectroscopymodule according to claim 1, wherein the light passing hole is formed sothat the light incident opening includes the light emitting opening ofthe light passing hole when viewed from a direction of its center line,and the light transmissive plate covers a part of the light incidentopening so as to include the light emitting opening when viewed from thedirection of the center line.
 3. The spectroscopy module according toclaim 1, wherein a light absorbing layer having a first light passingportion through which the light advancing to the spectroscopic portionpasses, and a second light passing portion through which the lightsadvancing to the light detecting portion of the light detecting elementpass, is formed on the predetermined plane.
 4. The spectroscopy moduleaccording to claim 1, further comprising a wiring board attached to thepredetermined plane, wherein an opening portion into which the lightdetecting element is disposed is formed, and a wiring electricallyconnected to the terminal electrodes is provided in the wiring board.